This invention relates to protective sheaths and, more particularly, a protective sheath having cobalt and phosphorus for resisting erosion of propeller blades, vanes, turbine blades, or other airfoil components.
Airfoil-shaped components are used in various types of aircraft for propeller blades and engine components such as vanes and blades. The airfoil components are typically located within an air stream that may include foreign objects such as sand, ice, water droplets, stones, birds, or other debris. The foreign objects strike the airfoil component, particularly a leading edge of the airfoil component. Over time, the foreign object strikes may cause mechanical damage that changes the shape of the airfoil component, which is detrimental to aerodynamic efficiency. Airfoil components that are made of polymer composites may be particularly vulnerable to erosion because of the relatively soft nature of a polymer composite, although components made of other types of material are also vulnerable.
To protect the airfoil component, a sheath may be used on the leading edge of the airfoil component to resist erosion. Typically, the sheath is made from a hard material that can withstand cracking, fracture, chipping, and breaking from impact with the foreign objects.
Although conventional sheaths have been effective, there is a desire for improving erosion resistance to increase the durability and useful life of airfoil components. The erosion resistance available by using conventional sheaths is limited by the material used to make the sheath. For example, conventional sheaths have been made from titanium alloys or nickel alloys, which only provide limited sheath hardness and sheath strength for protecting the airfoil component.
Accordingly, there is a need for a sheath having a composition that provides enhanced erosion resistance for protecting airfoil components. This invention addresses those needs while avoiding the drawbacks and shortcomings of the prior art.